1. Field of the Invention
The present invention relates to an accompaniment apparatus capable of performing automatic musical accompaniment by playing back memorized accompaniment chord progression patterns, and more particularly to such an accompaniment apparatus storing chord variety progression patterns for respective types of chords and automatically introducing variousness in the chord progression based on even a simple chord progression consisting of a small number of chords which are designated by the musical instrument player using a keyboard or the like.
2. Description of the Prior Art
Among conventional musical instruments having the function of automatic accompaniment, there is such a kind of musical instrument that stores accompaniment patterns constituted by note codes representing a progression of chords in a normalized tonality key, detects the chords played by the player based on the manipulated keys in the chord region (e.g. lower side keyboard region), and converts the note codes of the normalized accompaniment patterns based on the root note and the type of the detected chord to provide an automatic accompaniment with a proper chord progression as matches the designated chords. As the ways of designating (inputting) the chords through the keyboard manipulation, there are various types such as a type usually referred to as a "fingered chord" method in which the keys of the all constituent notes of a chord are actually depressed to designate an intended chord and a type usually referred to as a "single finger" method in which minimal (usually one, two or three) keys are depressed according to the predetermined designation rule to designate an intended chord. Among these, the "fingered chord" mode is for the advanced level players, while the "single finger" mode is for the beginners by way of easier chord designation.
The "single finger" mode designation, however, can designate only a few types of simple fundamental chords such as a major chord, a minor chord, a seventh chord and a minor seventh chord, and thus involves a problem that an automatic accompaniment with versatile variations may not be possible as it lacks ways of designating complicated chords and consequently lacks ways of composing a complex chord progression.